NPS, such as mephedrone (meow meow) and spice, used to be available to buy legally in "head shops" (shops that sell drug paraphernalia) or online.

Since the Psychoactive Substances Act came into effect on May 26 2016 it has been illegal to supply any NPS in the UK for human consumption. This includes selling them or giving them away for free.

Alcohol, medicines, nicotine, caffeine and poppers (alkyl nitrites) are exempt from the act.

How do NPS make you feel?

The main effects of almost all psychoactive drugs, including NPS, fall into three categories:

stimulants

"downers" or sedatives

psychedelics or hallucinogens

Synthetic cannabinoids, which can have both sedative and psychedelic effects, are sometimes separated out into their own category. They have been a big part of the NPS market and have been particularly problematic and harmful.

Even NPS that look similar or have similar names can vary in strength and can have different effects on different people.

How do NPS affect your health?

For lots of NPS, there has been little or no research into the short- or long-term health risks from human consumption and some risks aren't yet known.

Forensic testing of NPS has shown that they often contain different substances to what the packaging says, or mixtures of different substances.

This means you can never be sure what you are taking or what the effects might be.

Risks include:

NPS can reduce your inhibitions, so you may do potentially harmful things you wouldn't normally do.

They can cause paranoia, coma, seizures and, in rare cases, death.

You can never be sure of what is in an NPS, so you can't be sure what you've bought or been given, or what effect it's likely to have on you or your friends.

Cannabis (hash, weed, grass, skunk, marijuana)

What is cannabis?

Cannabis is a calming drug that also alters perceptions. It's seen as "natural" because it's made from the cannabis plant, but that doesn't mean it's safe. It can be smoked, often with tobacco, in a "joint" or "spliff", or in a pipe or "bong". It can also be drunk as a "tea" or eaten when mixed with food, such as biscuits or cakes.

How does cannabis make you feel?

Cannabis can make you feel relaxed and happy, but sometimes makes people feel lethargic, very anxious and paranoid, and even psychotic.

How does cannabis affect your health?

Cannabis has been linked to mental health problems such as schizophrenia and, when smoked, to lung diseases including asthma.

It affects how your brain works, so regular use can make concentration and learning very difficult. Frequent use can have a negative effect on your fertility.

It is also dangerous to drive after taking cannabis. Mixing it with tobacco is likely to increase the risk of heart disease and lung cancer.

Can cannabis be addictive?

Yes, it is possible to become psychologically dependent on cannabis. And some people do experience withdrawal symptoms when they stop taking it. For information about coming off drugs, read Drug addiction: getting help. You can also get help cutting down from the FRANK website.

Cocaine (powder cocaine, coke, crack)

What is cocaine?

Powder cocaine (coke), freebase and crack are all types of cocaine, and all are powerful stimulants. Freebase and crack can be smoked, and powder cocaine can be snorted in lines. Both cocaine powder and crack can also be prepared for injecting.

How does cocaine make you feel?

Cocaine gives the user energy, a feeling of happiness and being wide awake, and an overconfidence that can lead to taking risks. The effects are short-lived, so more drug is taken, which is often followed by a nasty "comedown" that makes you feel depressed and unwell, sometimes for several days.

How does cocaine affect your health?

If you take cocaine, it's possible to die of an overdose from overstimulating the heart and nervous system, which can lead to a heart attack. It can be more risky if mixed with alcohol.

Taking cocaine is particularly risky if you have high blood pressure or already have a heart condition. If you're pregnant, cocaine can harm your baby and even cause miscarriage. If you've had previous mental health problems, it can increase the chance of these returning.

If you snort cocaine, it can damage the cartilage of your nose over time. If you inject it, you are at higher risk of dying as the result of an overdose, and your veins and body tissues can be seriously damaged. You put yourself at risk of catching HIV or hepatitis if you share needles.

Can cocaine be addictive?

Yes, cocaine is highly addictive and can cause a very strong psychological dependence. For advice on getting help for cocaine addiction, go to Cocaine: get help. The Cocaine Anonymous website also offers further advice.

Ecstasy (MDMA, pills, crystal, E)

What is ecstasy?

Ecstasy is a "psychedelic" stimulant drug usually sold as tablets, but it's sometimes dabbed on to gums or snorted in its powder form. It's also known as MDMA or "crystal".

How does ecstasy make you feel?

Ecstasy can make you feel alert, affectionate and chatty, and can make music and colours seem more intense. Taking ecstasy can also cause anxiety, confusion, paranoia and even psychosis.

How does ecstasy affect your health?

Long-term use has been linked with memory problems, depression and anxiety. Ecstasy use affects the body's temperature control and can lead to dangerous overheating and dehydration.

But a balance is important as drinking too much fluid can also be very dangerous for the brain, particularly because ecstasy tends to stop your body producing enough urine, so your body retains the fluid. For more information on ecstasy, visit the FRANK website.

Is ecstasy addictive?

Ecstasy can be addictive, as users can develop a psychological dependence on this drug. It is also possible to build up a tolerance to the drug and need to take more and more to get the same effect.

Speed (amphetamine, billy, whizz)

What is speed?

Speed is the street name for drugs based on amphetamine, and is a stimulant drug. It's usually an off-white or pink powder that's either dabbed on to gums, snorted or swallowed in paper.

How does speed make you feel?

Speed can make you feel alert, confident and full of energy, and can reduce appetite. But it can make you agitated and aggressive, and can cause confusion, paranoia and even psychosis. You can also become very depressed and lethargic for hours or days after a period of heavy use.

How does speed affect your health?

Taking speed can be dangerous for the heart, as it can cause high blood pressure and heart attacks. It can be more risky if mixed with alcohol, or if it's used by people who have blood pressure or heart problems.

Injecting speed is particularly dangerous, as death can occur from overdose. Speed is usually very impure and injecting it can cause damage to veins and tissues, which can also lead to serious infections in the body and bloodstream. Any sharing of injecting equipment adds the risk of catching hepatitis C and HIV.

Is speed addictive?

Regular use of amphetamines can become highly addictive.

Further information

The following articles provide help and advice if you're concerned about your own or someone else's drug misuse: